Vtec crossover?

ok so wats a good point to have vtec crossover. id like peoples opion and wat they have there vtec crossing over and if it pulls hard and wat not.

unless you have some internal work, then leave it stock.
Honda set it where it is from factory for a reason, so unless you have cams and pistons, i’d leave it where it is. Setting VTEC to engage sooner does not mean your car is faster.

yea just leave it stock. i have a chipped ecu that lowered vtec engagement to 4400 from the stock 4900 and i dont like it. i’d actually rather have it higher at like 5200.
when mine engages all you can hear is loudness for a few hundred rpm then it starts to pull hard at like 5500. and i dont like the fact that when i’m on the interstate going like 85mph i’m riding in vtec, and thats just loud and a waste of gas.

to add to eclypz’s comment - i have a mugen program in my ecu, and even honda mechanic i know said it is useless unless i have at least mugen cams and some head work along with higher compression because those maps in the ecu are made specifically for a race motor like that. so i just waste a lot of gas and make a lot of noise lol. i only noticed a gain way up at like 6500+rpm. oh well it was a free ecu so i cant complain.

I’m a hondata dealer and know the OEM honda ECU every well. The vtec ecu uses two independant fuel and ignition maps. When the right creteria is met the low speed cam’s fuel and ignition tables switch to the high speed cam’s fuel and ignition. The ecu controls the switch via the vtec solenoid but has no way of monitoring if it has really engaged vtec or not. If you were to purchase a vtec controller you can control vtec crossover but the ecu will switch the tables when it meets its demands.

Most of the time when I tune the systems I engage vtec only over 6" of vacuum. This helps out significantly for cruising when vtec is not required and the swirl within the combustion chamber helps boost the midrange torque and fuel mileage.

I run a modified ITR head with a stock B18C5 on my DA. I have my vtec crossover point set for 5K with a redline of 9K. The launch is set for 3.2K and full throttle shift set for 6K (I don’t play with this feature much). Fortunately, on boosted ITRs I can set the vtec at arround 4.4K and the torque of the low cam and high cam interlace beautifully. The boost kicks up 2-3 psi instantly when the vtec engages and the vehicle pulls gracefully but the vtec is set not to function when the car is cruising.

I hope this helps.


uhm… is something wrong with the ecu then? Vtec shouldnt kick in unless your full throttle…

VTEC can engage at partial throttle on a b-series.
Not sure on a K, though.

What he said… it can engage at part throttle, but it has to be over a certain percentage of throttle.

yea i’m with them, you dont need to be at WOT. i was going down a huge hill a while ago in 2nd gear and coasted into vtec, thats NO throttle. i like to hear it slowly pop open at partial throttle it sounds cool, i do it all the time. :dance:

i just realized you said it has to be a certain percentage of throttle… i have a chipped ecu that lets me do a lot of cool shit so that probably why.

Do you have it tuned for the “boost kick” to come on when vtec engages? Just a note, I’ve read that boosted applications don’t like high lift and long duration. Might want to try to have the vtec not engage at all.

I’m uberdata tuned, and haven’t noticed anything like that. Then again, I never spend my time above 2500 rpms unless I’m at the strip.

how do you pull that off? can’t even go 60 in 5th below 2500 rpm.

More like 45 in 5th. I go no more than 35 anywhere I go, all of my driving is strictly city driving.

i dont know haha. i like to play around in the back roads here in the north GA hills and see what my car can do. the first time i tired to coast into vtec it sounded like it got stuck engaging lol the tach stopped at 4400 and made a weird robot sounding noise and then went up to like 5000.

and i hit vtec with cruise control a few times. its limited though, it was just like the rev limiter but it stopped at like 5500 or something i dont remember.
i can hit vtec in neutral too hehe but i dont do that very often because i’m not sure if its good to have no load on the motor when revving like that. i just like to scare off ricers with it.